How Small Community Parks May Make Cities Safer, More Healthy

A study from the Perelman School of Medicine at the University of Pennsylvania has found that green spaces are linked to reduced crime rates

A research team has found that distressed neighborhoods where vacant
lots have been converted into small parks and community green spaces are
associated with reduced crime when compared to neighborhoods with
unimproved vacant lots. The study was conducted by a group from the
University of Pennsylvania's Perelman School of Medicine, using
Philadelphia data compiled over the last decade. In some sections of
the city, residents of neighborhoods with improved vacant lots also
reported "significantly less stress and more exercise," suggesting that
the improvements had an effect on residents' perceptions of safety
outdoors.

Philadelphia has a major program
to take advantage of vacant lots within the city to add 500 acres of
additional neighborhood parks, gardens, and other green space by the end
of 2015. In addition, according to a press release issued by the Perelman School, the Pennsylvania Horticultural Society has had a program to green abandoned vacant lots
in the city since 1999. Nearly 4,500 vacant lots totaling over 7.8
million square feet were greened from 1999 to 2008. The Horticultural
Society's inventory of work formed the basis for the new study:

This program involved removing trash and debris, grading the land, planting grass and trees to create a park-like setting, and installing low wooden post-and-rail fences
around each lot to show that it was cared for and to deter illegal
dumping. Several times a year, PHS returned to each greened lot to
perform basic maintenance, such as mowing the grass, tending trees, or
repairing fences.

[Penn's Dr. Charles C.] Branas and his team analyzed the impact
of this program for a decade, from 1999 to 2008, using a statistical
design that considered various health and safety outcomes and numerous
other factors occurring on and around vacant lots, before and after they
were treated, as compared to vacant lots that were not greened over the
same time period.

A control group of unimproved vacant lots was selected with a
methodology designed to ensure fair comparability to the greened lots. The study, which was published earlier this month in the American Journal of Epidemiology,
correlated the lots with data from the Philadelphia Police Department
and the Southeastern Pennsylvania Household Health Survey.

Vacant lot greening was associated with significant reductions in gun
assaults across all four sections of Philadelphia in the study and with
significant reductions in vandalism in one section. Greening was also
associated with the reporting of significantly less stress in one of the
sections of the city and with more exercise in another. Cholesterol
numbers were lower to a statistically significant degree for the greened
areas across all four city sections.

Increased incidents of disorderly conduct, on the other hand, were
associated with greening. The research team suggests that this might be
understandable. From the press release:

A greened lot may serve as a new opportunity for community
gatherings, bringing large groups of people together and increasing the
opportunity for crowd-based nuisance crimes such as disorderly conduct,
say the researchers. Community interest in maintaining a newly greened
lot may have also increased calls to police and arrests for disorderly
conduct.

An earlier, smaller study conducted by researchers from Texas State and Texas A&M, and reported two years ago in Science Daily,
was unable to find a statistically significant correlation between
eleven Houston neighborhoods with community gardens and reduced rates in
reported crime when compared to a control group of neighborhoods without gardens. Even that study, however, found that the residents of neighborhoods
with gardens "linked the presence of the gardens to ... perceived
immunity from crime, noting changes such as the cessation of illegal
activity, including dumping and/or drug activity, increased property
values, and increased neighborhood redevelopment."

The Texas researchers also noted that other studies have revealed an
increase in the number of owner-occupied dwellings, more personal income
(as a result of attracting people with higher incomes to the
community), and rent increases in areas surrounding community gardens. The Philadelphia team noted that a range of studies have shown that the
presence of urban green space is linked to lower rates of mortality and
health complaints and to mental health benefits.

My take is that it undoubtedly takes more than increased, tended
green space to cure crime and other problems associated with distressed
neighborhoods and vacant lots. But I suspect we are also seeing the
beginnings of evidence that it is among the things that can help.

Here's a very good, short video from the Pennsylvania Horticultural
Society showing examples from their neighborhood greening program:

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Kaid Benfield is the director of the Sustainable Communities and Smart Growth program at the Natural Resources Defense Council, co-founder of the LEED for Neighborhood Development rating system, and co-founder of Smart Growth America.